Measurements of the (n,2n) Reaction Cross Section of 181Ta from 8 to 15 MeV

The cross section for the reaction Ta-181(n,2n) Ta-180(g) was measured from 8 to 15 MeV in small energy steps to resolve inconsistencies in the existing databases. The activation technique was used, and the 93.4 keV gamma-ray from the decay of the Ta-180(g) ground state was recorded with a HPGe detector. In addition, the gamma-rays from the monitor reactions Al-27(n,alpha)Na-24 and Au-197(n,2n) Au-196 were measured for neutron fluence determination. As a cross check, a calibrated neutron detector was also used. The ENDF/B-VII. 1 and TENDL-2011 evaluations are in considerable disagreement with the present data, which in turn agree very well with the majority of the existing data in the 14 MeV energy region.